Comparative evaluation of a lower dose CBCT acquisition protocol for preoperative implant site assessment in dry human skulls.

Restoration of edentulous sites with dental implants is increasingly becoming a popular choice. Cross-sectional 3D imaging using CBCT provides a superior view of the implant site to help the clinician plan the procedure better. In spite of the advantages, radiation dose remains a concern. The evolution of lower dose protocols is ongoing but whether those acquisition protocols yield comparable diagnostic information is still not well established. The objective of this study was to evaluate the diagnostic efficacy of a low dose, 180˚ rotational CBCT acquisition protocol for evaluating a potential implant site in comparison with a conventional 360˚ rotational acquisition. Ten dentate and partially edentulous dry human skulls were chosen for this study. Each skull was imaged using a 360˚ and a 180˚ rotational acquisition on a J. Morita's Accuitomo CBCT scanner. 82 randomized implant sites, 40 in the maxilla and 42 in the mandible were analyzed. Evaluation of cortical and trabecular bone, proximity to crucial structures such as the inferior alveolar nerve canal and the maxillary sinus, and width of the potential placement site were measured. An oral surgeon and an oral radiologist rated the diagnostic efficacy of the scans by evaluating the above characteristics. Statistical evaluation of the data with linear regression showed significant agreement between both protocol measurements. Kappa analyses yielded a good inter-observer agreement. In this ex-vivo study, there was no significant difference in both the qualitative and quantitate evaluation between the conventional 36 0˚ acquisition protocol and  the modified lower dose 180˚ rotational protocol.